Wanted: feedback from drivers late model 300-340 Cummins

I have a 340 / 2500 combination and it never down shifts on overpasses or slight inclines It will down shift 6 to 5 in the hills but one would need to see it on the shift pad to know it happened.
As for increasing HP and torque, any Oasis shop can do it for about $450.00, its a simple program download. My son had his done last summer on his 2014 Excursion. Went from 300 hp 650 torque to 325 hp and 750 torque.